The grainy video from a security camera on a South Side home and released Tuesday by the Civilian Office of Police Accountability shows Sgt. Khalil Muhammad shooting 18-year-old Ricardo Hayes around 5 a.m. on Aug. 13, 2017.

Before the shooting, Hayes can be seen running along the sidewalk then stopping. Muhammed pulls up alongside, with parked cars between them. Hayes takes a few steps toward him and Muhammed shoots the teen in the arm and chest. Hayes turns and runs, despite his wounds.

A lawsuit filed by the American Civil Liberties Union and another on behalf of Hayes and his family say his caretaker had called police to say Hayes had wandered away from home and that he has developmental disabilities.

"As a black teenager with disabilities, Ricky was at a heightened risk for police violence," Karen Sheley of the ACLU of Illinois said in a statement. "Thankfully, he survived - but he should never have been shot."

At the time, police officials described the incident as an armed confrontation, mirroring statements by officers after the fatal shooting of the 17-year-old McDonald in November 2014. Jason Van Dyke was convicted earlier this month of second-degree murder and aggravated battery in the slaying. Despite video evidence to the contrary, Van Dyke and other officers on the scene claimed McDonald was acting aggressively before the shooting. Van Dyke said the teenager lunged at him with a pocket knife.

The sergeant's call to 911 after he shot Hayes in the summer of 2017 was among the audio files released this week.

"The guy, like, he was about to pull a gun. Walked up to the car, and I had to shoot," Muhammad told a Chicago Fire Department dispatcher. But according to the lawsuit filed by Hayes and his family, the teen "was standing almost perfectly still, facing Officer Muhammad's truck, with his hands at his sides" when he was shot.

And, said Sheley, "the video shows both that there was no justification for the officer to shoot him and that initial stories told by CPD officials about the shooting - that the 'encounter escalated' - were false."

Police Superintendent Eddie Johnson later said Hayes had no weapon and, on Wednesday, department spokesman Anthony Guglielmi said Johnson will be asking Muhammad why he opened fire from inside his SUV - something officers are trained to do only if there is an imminent threat.

"Certainly, discharging the weapon from the vehicle is going to have to be explained," he said.

The Cook County State's Attorney's Office has decided to not prosecute the sergeant, COPA spokesman Ephraim Eaddy said Wednesday. The state's attorney's office has not returned a call for comment.

When the shooting happened, the police force was in the process of training officers on how to handle people with mental health issues. That training was prompted by a 2015 incident in which a police officer fatally shot a 55-year-old innocent bystander and teenager with a baseball bat who was suffering a mental health episode.

Guglielmi said Muhammad had not received the training at the time he shot Hayes. And even if he had, Muhammad was off-duty at the time and so would not have known about the 911 call, and he couldn't have known that Hayes is autistic because he didn't interview the young man.

Under the many police reforms launched to regain public trust following the McDonald shooting, the materials that COPA released this week are supposed to be made public within 60 days . But in a statement, the agency said it delayed releasing the video and related material because of concerns about the legality of releasing of information related to wards of the state.

Guglielmi said that Muhammad is on administrative leave pending the outcome of the COPA investigation.

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